1. Field of the Invention
The present invention relates, to a plastic product painting mask used for applying a painting treatment to a desired portion of a plastic molding such as a lens, a decorative frame, or the like, which is a constituent part of a lighting tool for a vehicle.
2. Description of the Related Art
To apply painting to a plastic product which is part of a lighting tool for a vehicle, a painting mask is disposed on a molding (work), and a predetermined area of the molding is painted with a spray gun or the like, by way of example. Then, in a conventional painting mask, a nickel mask is used in which an edge portion for defining a painting area parting line is formed. Such a conventional mask was generally formed into a predetermined shape corresponding to the external shape of the work by electro-casting.
However, although the above-mentioned conventional painting mask was very high in dimensional accuracy because it was produced by electro-casting, there was a problem in that large-scale manufacturing equipment was required and it took a great deal of time to manufacture.
The present invention was developed taking into consideration the foregoing problem related to the conventional painting mask. Accordingly, it is an object of the present invention to provide a plastic product painting mask which is easy to manufacture, and which has a predetermined dimensional accuracy with a configuration in which a mask body base portion is formed of a metal plate with a dimension substantially matching the work, and another configuration in which a painting area circumferential edge portion having an edge portion for defining a painting area parting line is formed out of plastic.
In order to achieve the above object, the present invention includes a lighting tool painting mask in which an edge portion for defining a painting area parting line is formed in a mask body of a predetermined-size covering a work made from plastic, wherein the mask body is constituted by a mask body base portion composed of a metal plate with a dimension substantially matching the work, and a painting area circumferential edge portion molded out of plastic integrally with the mask body base portion, the painting area circumferential edge portion having the edge portion for defining a painting area parting line formed therein.
In the plastic product painting mask of the present invention, the work is a constituent part of a lighting tool for a vehicle, and the painting area circumferential edge portion is molded by solidifying the plastic which is prepared like clay.
Although the painting area circumferential edge portion made from plastic can be molded integrally with a predetermined portion of the mask body base portion, the plastic which is prepared like clay is applied to a predetermined portion of the mask body base portion and solidified so that the painting area circumferential edge portion can be molded integrally with the mask body base portion, the mask body base portion being composed of a metal plate which does not shrink in on itself as in the case of a plastic. Accordingly, the mask body as a whole can be formed with an appropriate dimension.
In addition, even if there is a failure in cuttingxe2x80x94for example, even if the painting area circumferential edge portion made from plastic is cut excessivelyxe2x80x94the painting mask can be restored easily by applying the clay-like plastic again.
Further, in the plastic product painting mask of the present invention, a bonding portion between the mask body base portion and the painting area circumferential edge portion is configured in a form where a side edge portion of the mask body base portion is buried in the painting area circumferential edge portion.
The side edge portion of the mask body base portion is surrounded by a plastic layer which constitutes the painting area circumferential edge portion, so that the bonding strength between the mask body base portion and the painting area circumferential edge portion is high.
In addition, in the case where the mask body is used in a painting step, it is difficult to damage the work because the painting area circumferential edge portion in contact with the work is composed of plastic.
In the plastic product painting mask according to the present invention, the plastic prepared. like clay in hardness is molded and solidified along a painting-presumptive area of the work while being pressed on the painting-presumptive area tightly, so that the painting area circumferential edge portion is integrated with the mask body base portion.
If the mask body base portion is disposed on the work and the plastic prepared like clay is molded and solidified along the side edge portion of the mask body base portion while being pressed thereon tightly, other painting area circumferential edge portion can be molded integrally with the side edge of the mask body base portion easily. After that, the edge portion for defining a painting area parting line may. be formed in the painting area circumferential edge portion by cutting.
Still further, in the plastic product painting mask of the present invention, the plastic is composed of epoxy resin into which a curing agent is mixed.
In the present invention, epoxy resin is used as it is easy to be solidified by a curing agent, and low in molding shrinkage. Further, no by-product is produced when epoxy resin is solidified. In addition, epoxy resin has extremely excellent adhesion properties and superior mechanical properties.